Software Architecture Patterns for a Context-Processing Middleware Framework

Ubiquitous applications are characterized by variations in their execution context. Their correct operation requires some continual adaptations based on the observation of this context. The design and implementation of these observation policies is thus the cornerstone of any ubiquitous application. COSMOS is a component-based framework for managing context information in ubiquitous context-aware applications. COSMOS decomposes context observation policies into fine-grained units called context nodes, which it implements as software components. These units perform basic context-related operations, such as gathering data from a system or network probe and computing threshold or average values. The framework assembles these units with a set of well-identified architectural design patterns. A mobile computing scenario illustrates the framework's benefits.